Methods of Forming Wrapped Yarns and Ropes Having Predetermined Surface Characteristics

ABSTRACT

A plurality of first fibers and a plurality of second fibers are provided. A coefficient of friction of the second fibers is greater than a coefficient of friction of the first fibers. Abrasion resistance characteristics of the second fibers are greater than abrasion resistance properties of the first fibers. A gripping ability of the second fibers is greater than a gripping ability of the first fibers. The first fibers and the second fibers are passed through a convergence duct such that the first fibers pick up the second fibers. A false twist is imparted to the combination of the plurality of first fibers and the plurality of second fibers. The false twist is removed from the combination of the plurality of first fibers and the plurality of second fibers to form the blended yarn.

RELATED APPLICATIONS

This application (Attorney's Ref. No. P218806) is a continuation of U.S.patent application Ser. No. 14/262,600 filed Apr. 25, 2014, currentlypending.

U.S. patent application Ser. No. 14/262,600 is a continuation of U.S.patent application Ser. No. 13/466,994 filed May 8, 2012, now U.S. Pat.No. 8,707,668, which issued on Apr. 29, 2014.

U.S. patent application Ser. No. 13/466,994 is a continuation of U.S.patent application Ser. No. 12/815,363 filed Jun. 14, 2010, now U.S.Pat. No. 8,171,713, which issued on May 8, 2012.

U.S. patent application Ser. No. 12/815,363 is a continuation of U.S.patent application Ser. No. 12/151,467 filed on May 6, 2008, now U.S.Pat. No. 7,735,308, which issued on Jun. 15, 2010.

U.S. patent application Ser. No. 12/151,467 is a continuation of U.S.patent application Ser. No. 11/599,817 filed on Nov. 14, 2006, now U.S.Pat. No. 7,367,176, which issued on May 6, 2008.

U.S. patent application Ser. No. 11/599,817 is a continuation of U.S.patent application Ser. No. 10/903,130 filed on Jul. 30, 2004, now U.S.Pat. No. 7,134,267, which issued on Nov. 14, 2006.

U.S. patent application Ser. No. 10/903,130 claims benefit of U.S.Provisional Application Ser. No. 60/530,132 filed on Dec. 16, 2003.

The contents of all related applications listed above are incorporatedherein by reference.

TECHNICAL FIELD

The present invention relates to rope systems and methods and, inparticular, to wrapped yarns that are combined to form strands formaking ropes having predetermined surface characteristics.

BACKGROUND

The characteristics of a given type of rope determine whether that typeof rope is suitable for a specific intended use. Rope characteristicsinclude breaking strength, elongation, flexibility, weight, and surfacecharacteristics such as abrasion resistance and coefficient of friction.The intended use of a rope will determine the acceptable range for eachcharacteristic of the rope. The term “failure” as applied to rope willbe used herein to refer to a rope being subjected to conditions beyondthe acceptable range associated with at least one rope characteristic.

The present invention relates to ropes with improved surfacecharacteristics, such as the ability to withstand abrasion or to providea predetermined coefficient of friction. Typically, a length of rope isconnected at first and second end locations to first and secondstructural members. Often, the rope is supported at one or moreintermediate locations by intermediate structural surfaces between thefirst and second structural members. In the context of a ship, theintermediate surface may be formed by deck equipment such as a closedchock, roller chock, bollard or bit, staple, bullnose, or cleat.

When loads are applied to the rope, the rope is subjected to abrasionwhere connected to the first and second structural members and at anyintermediate location in contact with an intermediate structural member.Abrasion and heat generated by the abrasion can create wear on the ropethat can affect the performance of the rope and possibly lead to failureof the rope. In other situations, a rope designed primarily for strengthmay have a coefficient of friction that is too high or low for a givenuse. The need thus exists for improved ropes having improved surfacecharacteristics, such as abrasion resistance or coefficient of friction;the need also exists for systems and methods for producing such ropes.

SUMMARY

The present invention may be embodied as a method of forming a blendedyarn comprising the following steps. A plurality of first fibers and aplurality of second fibers are provided. The first fibers are sized toextend along a length of the blended yarn. The second fibers are sizedto extend only partly along a length of the blended yarn. A coefficientof friction of the second fibers is greater than a coefficient offriction of the first fibers. Abrasion resistance characteristics of thesecond fibers are greater than abrasion resistance properties of thefirst fibers. A gripping ability of the second fibers is greater than agripping ability of the first fibers. A combination of the plurality offirst fibers and the plurality of second fibers is formed by passing theplurality of first fibers and the plurality of second fibers through aconvergence duct such that the first fibers pick up the second fibers. Afalse twist is imparted to the combination of the plurality of firstfibers and the plurality of second fibers by passing the combination ofthe plurality of first fibers and the plurality of second fibers througha false-twisting device. The false twist is removed from the combinationof the plurality of first fibers and the plurality of second fibers toform the blended yarn.

The present invention may also be embodied as a method of forming a ropecomprising the following steps. First and second sets of first fibersare provided. The first and second sets of fibers are combined to form aplurality of wrapped yarns such that the first set of the first fibersforms a core that is substantially surrounded by the second set, thefirst fibers substantially determine the load bearing characteristics ofthe rope, and the second fibers substantially determine abrasionresistance properties and gripping ability of the rope. A tension loadis applied on the rope such that the tension loads on the rope areprimarily borne by the first fibers. The second fibers substantiallydetermine friction, abrasion resistance, and gripping ability of therope.

The present invention may also be embodied as a method of forming ablended yarn comprising the following steps. A plurality of first fibersand a plurality of second fibers are selected such that a coefficient offriction of the second fibers is greater than a coefficient of frictionof the first fibers, abrasion resistance characteristics of the secondfibers are greater than abrasion resistance properties of the firstfibers, and a gripping ability of the second fibers is greater than agripping ability of the first fibers. The plurality of second fibers iscombined with the plurality of first fibers using a false-twistingprocess such that the first fibers extend along the length of theblended yarn and the second fibers do not extend along the length of theblended yarn and at least a portion of the second fibers are engagedwith and extend from the plurality of first fibers effectively to definesurface characteristics of the blended yarn. A tension load is appliedto the blended yarn such that the tension loads on the blended yarn areprimarily borne by the first fibers and the second fibers substantiallydetermine friction, abrasion resistance, and gripping ability of theblended yarn.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a side elevation view of a wrapped yarn that may be used toconstruct a rope of the present invention;

FIG. 1B is an end elevation cutaway view depicting the yarn of FIG. 1A;

FIG. 2 is a side elevation view of a first example of a rope of thepresent invention;

FIG. 3 is a radial cross-section of the rope depicted in FIG. 2;

FIG. 4 is a close-up view of a portion of FIG. 3;

FIG. 5 is a side elevation view of a second example of a rope of thepresent invention;

FIG. 6 is a radial cross-section of the rope depicted in FIG. 5;

FIG. 7 is a close-up view of a portion of FIG. 6;

FIG. 8 is a side elevation view of a first example of a rope of thepresent invention;

FIG. 9 is a radial cross-section of the rope depicted in FIG. 8;

FIG. 10 is a close-up view of a portion of FIG. 9; and

FIG. 11 is a side elevation view of a first example of a rope of thepresent invention;

FIG. 12 is a radial cross-section of the rope depicted in FIG. 8;

FIG. 13 is a close-up view of a portion of FIG. 9; and

FIG. 14 is a schematic diagram representing an example process offabricating the yarn depicted in FIGS. 1A and 1B.

DETAILED DESCRIPTION

Referring initially to FIGS. 1A and 1B of the drawing, depicted thereinis a blended yarn 20 constructed in accordance with, and embodying, theprinciples of the present invention. The blended yarn 20 comprises atleast a first set 22 of fibers 24 and a second set 26 of fibers 28.

The first and second fibers 24 and 28 are formed of first and secondmaterials having first and second sets of operating characteristics,respectively. The first material is selected primarily to providedesirable tension load bearing characteristics, while the secondmaterial is selected primarily to provide desirable abrasion resistancecharacteristics.

In addition to abrasion resistance, the first and second sets ofoperating characteristics can be designed to improve othercharacteristics of the resulting rope. As another example, certainmaterials, such as HMPE, are very slick (low coefficient of friction).In a yarn consisting primarily of HMPE as the first set 22 for strength,adding polyester as the second set 26 provides the resulting yarn 20with enhanced gripping ability (increased coefficient of friction)without significantly adversely affecting the strength of the yarn 20.

The first and second sets 22 and 26 of fibers 24 and 28 are physicallycombined such the first set 22 of fibers 24 is at least partlysurrounded by the second set 26 of fibers 28. The first fibers 24 thusform a central portion or core that is primarily responsible for bearingtension loads. The second fibers 28 form a wrapping that at least partlysurrounds the first fibers 24 to provide the rope yarn 20 with improvedabrasion resistance.

The example first fibers 24 are continuous fibers that form what may bereferred to as a yarn core. The example second fibers 28 arediscontinuous fibers that may be referred to as slivers. The term“continuous” indicates that individual fibers extend along substantiallythe entire length of the rope, while the term “discontinuous” indicatesthat individual fibers do not extend along the entire length of therope.

As will be described below, the first and second fibers 24 and 28 may becombined to form the example yarn using a wrapping process. The exampleyarn 20 may, however, be produced using process for combining fibersinto yarns other than the wrapping process described below.

With the foregoing understanding of the basic construction andcharacteristics of the blended yarn 20 of the present invention in mind,the details of construction and composition of the blended yarn 20 willnow be described.

The first material used to form the first fibers 24 may be any one ormore materials selected from the following group of materials: HMPE,LCP, or PBO fibers. The second material used to form the second fibers28 may be any one or more materials selected from the following group ofmaterials: polyester, nylon, Aramid, LCP, and HMPE fibers.

The first and second fibers 24 and 28 may be the same size or either ofthe fibers 24 and 28 may be larger than the other. The first fibers 24are depicted with a round cross-section and the second fibers 28 aredepicted with a flattened cross-section in FIG. 1B for clarity. However,the cross-sectional shapes of the fibers 24 and 28 can take forms otherthan those depicted in FIG. 1B. The first fibers 24 are preferablygenerally circular. The second fibers 28 are preferably also generallycircular.

The following discussion will describe several particular example ropesconstructed in accordance with the principles of the present inventionas generally discussed above.

First Rope Example

Referring now to FIGS. 2, 3, and 4, those figures depict a first exampleof a rope 30 constructed in accordance with the principles of thepresent invention. As shown in FIG. 2, the rope 30 comprises a rope core32 and a rope jacket 34. FIG. 2 also shows that the rope core 32 andrope jacket 34 comprise a plurality of strands 36 and 38, respectively.FIG. 4 shows that the strands 36 and 38 comprise a plurality of yarns 40and 42 and that the yarns 40 and 42 in turn each comprise a plurality offibers 44 and 46, respectively.

One or both of the example yarns 40 and 42 may be formed by a yarn suchas the abrasion resistant yarn 20 described above. However, because therope jacket 34 will be exposed to abrasion more than the rope core 32,at least the yarn 42 used to form the strands 38 should be fabricated atleast partly from the abrasion resistant yarn 20 described above.

The exemplary rope core 32 and rope jacket 34 are formed from thestrands 36 and 38 using a braiding process. The example rope 30 is thusthe type of rope referred to in the industry as a double-braided rope.

The strands 36 and 38 may be substantially identical in size andcomposition. Similarly, the yarns 40 and 42 may also be substantiallyidentical in size and composition. However, strands and yarns ofdifferent sizes and compositions may be combined to form the rope core32 and rope jacket 34.

As described above, fibers 44 and 46 forming at least one of the yarns40 and 42 are of two different types. In the yarn 40 of the example rope30, the fibers 44 are of a first type corresponding to the first fibers24 and a second type corresponding to the second fibers 28. Similarly,in the yarn 42 of the example rope 30, the fibers 46 are of a first typecorresponding to the first fibers 24 and a second type corresponding tothe second fibers 28.

Second Rope Example

Referring now to FIGS. 5, 6, and 7, those figures depict a secondexample of a rope 50 constructed in accordance with the principles ofthe present invention. As perhaps best shown in FIG. 6, the rope 50comprises a plurality of strands 52. FIG. 7 further illustrates thateach of the strands 52 comprises a plurality of yarns 54 and that theyarns 54 in turn comprise a plurality of fibers 56.

The example yarn 54 may be formed by a yarn such as the abrasionresistant yarn 20 described above. In the yarn 54 of the example rope50, the fibers 56 are of a first type corresponding to the first fibers24 and a second type corresponding to the second fibers 28.

The strands 52 are formed by combining the yarns 54 using any one of anumber of processes. The exemplary rope 50 is formed from the strands 52using a braiding process. The example rope 50 is thus the type of ropereferred to in the industry as a braided rope.

The strands 52 and yarns 54 forming the rope 50 may be substantiallyidentical in size and composition. However, strands and yarns ofdifferent sizes and compositions may be combined to form the rope 50.The first and second types of fibers combined to form the yarns 54 aredifferent as described above with reference to the fibers 24 and 28.

Third Rope Example

Referring now to FIGS. 8, 9, and 10, those figures depict a thirdexample of a rope 60 constructed in accordance with the principles ofthe present invention. As perhaps best shown in FIG. 9, the rope 60comprises a plurality of strands 62. FIG. 10 further illustrates thateach of the strands 62 in turn comprises a plurality of yarns 64,respectively. The yarns 64 are in turn comprised of a plurality offibers 66.

The example yarn 64 may be formed by a yarn such as the abrasionresistant yarn 20 described above. The fibers 66 of at least some of theyarns 64 are of a first type and a second type, where the first andsecond types and correspond to the first and second fibers 24 and 28,respectively.

The strands 62 are formed by combining the yarns 64 using any one of anumber of processes. The exemplary rope 60 is formed from the strands 62using a twisting process. The example rope 60 is thus the type of ropereferred to in the industry as a twisted rope.

The strands 62 and yarns 64 forming the rope 60 may be substantiallyidentical in size and composition. However, strands and yarns ofdifferent sizes and compositions may be combined to form the rope 60.The first and second types of fibers are combined to form at least someof the yarns 64 are different as described above with reference to thefibers 24 and 28.

Fourth Rope Example

Referring now to FIGS. 11, 12, and 13, those figures depict a fourthexample of a rope 70 constructed in accordance with the principles ofthe present invention. As perhaps best shown in FIG. 12, the rope 70comprises a plurality of strands 72. FIG. 13 further illustrates thateach of the strands 72 comprise a plurality of yarns 74 and that theyarns 74 in turn comprise a plurality of fibers 76, respectively.

One or both of the example yarns 74 may be formed by a yarn such as theabrasion resistant yarn 20 described above. In particular, in theexample yarns 74 of the example rope 70, the fibers 76 are each of afirst type corresponding to the first fibers 24 and a second typecorresponding to the second fibers 28.

The strands 72 are formed by combining the yarns 74 using any one of anumber of processes. The exemplary rope 70 is formed from the strands 72using a braiding process. The example rope 70 is thus the type of ropecommonly referred to in the industry as a braided rope.

The strands 72 and yarns 74 forming the rope 70 may be substantiallyidentical in size and composition. However, strands and yarns ofdifferent sizes and compositions may be combined to form the rope 70.The first and second types of fibers are combined to form at least someof the yarns 74 are different as described above with reference to thefibers 24 and 28.

Yarn Fabrication

Turning now to FIG. 14 of the drawing, depicted at 120 therein is anexample system 120 for combining the first and second fibers 24 and 28to form the example yarn 20. The system 120 basically comprises atransfer duct 122, a convergence duct 124, a suction duct 126, and afalse-twisting device 128. The first fiber 24 is passed between a pairof feed rolls 130 and into the convergence duct 124. The second fiber 28is initially passed through a pair of back rolls 142, a pair of draftingaprons 144, a pair of drafting rolls 146, and into the transfer duct122.

The example first fibers 24 are continuous fibers that extendsubstantially the entire length of the example yarn 20 formed by thesystem 120. The example second fibers 28 are slivers, or discontinuousfibers that do not extend the entire length of the example yarn 20.

The second fibers 28 become airborne and are drawn into convergence duct124 by the low pressure region within the suction duct 126. The firstfibers 24 converge with each other and the airborne second fibers 28within the convergence duct 124. The first fibers 24 thus pick up thesecond fibers 28. The first and second fibers 24 and 28 are thensubsequently twisted by the false-twisting device 128 to form the yarn20. The twist is removed from the first fibers 24 of the yarn 20 as theyarn travels away from the false-twisting device 128.

After the yarn 20 exits the false-twisting device 128 and the twist isremoved, the yarn passes through let down rolls 150 and is taken up by awindup spool 152. A windup roll 154 maintains tension of the yarn 20 onthe windup spool 152.

First Yarn Example

A first example of the yarn 20 that may be fabricated using the system120 as described above comprises the following materials. The firstfibers 24 are formed of HMPE fibers and the second fibers are formed ofpolyester fibers. The yarn of the first example comprises between aboutsixty to eighty percent by weight of the first fibers 24 and betweenabout twenty to forty percent by weight of the second fibers 28.

Second Yarn Example

A second example of the yarn 20 that may be fabricated using the system120 as described above comprises the following materials. The firstfibers 24 are formed of LCP fibers and the second fibers are formed of acombination of LCP fibers and Aramid fibers. The yarn of the secondexample comprises between about fifteen and thirty-five percent byweight of the first fibers 24 and between about sixty-five andeighty-five percent by weight of the second fibers 28. Morespecifically, the second fibers 28 comprise between about forty andsixty percent by weight of LCP and between about forty and sixty percentby weight of Aramid.

Given the foregoing, it should be clear to one of ordinary skill in theart that the present invention may be embodied in other forms that fallwithin the scope of the present invention.

What is claimed is:
 1. A method of forming a blended yarn comprising thesteps of: providing a plurality of first fibers, where the first fibersare sized to extend along a length of the blended yarn; and providing aplurality of second fibers, where the second fibers are sized to extendonly partly along a length of the blended yarn, a coefficient offriction of the second fibers is greater than a coefficient of frictionof the first fibers, abrasion resistance characteristics of the secondfibers are greater than abrasion resistance properties of the firstfibers, and a gripping ability of the second fibers is greater than agripping ability of the first fibers; forming a combination of theplurality of first fibers and the plurality of second fibers by passingthe plurality of first fibers and the plurality of second fibers througha convergence duct such that the first fibers pick up the second fibers;imparting a false twist to the combination of the plurality of firstfibers and the plurality of second fibers by passing the combination ofthe plurality of first fibers and the plurality of second fibers througha false-twisting device; removing the false twist from the combinationof the plurality of first fibers and the plurality of second fibers toform the blended yarn.
 2. A method as recited in claim 1, in which atleast a portion of the second fibers are engaged with and extend fromthe plurality of first fibers to define surface characteristics of theblended yarn.
 3. A method as recited in claim 1, in which step offorming the combination of the plurality of first fibers and theplurality of second fibers comprises the step of arranging the secondfibers to at least partly surround the first fibers.
 4. A method asrecited in claim 1, in which step of forming the combination of theplurality of first fibers and the plurality of second fibers comprisesthe step of forming a core comprising the first fibers, where the secondfibers surround the first fibers.
 5. A method as recited in claim 1, inwhich the second fibers comprise at least one fiber selected from thegroup of fibers consisting of polyester, nylon, Aramid, LCP, and HMPEfibers.
 6. A method as recited in claim 1, in which the second fibersare polyester fibers.
 7. A method as recited in claim 6, in which theblended yarn comprises about sixty to eighty percent by weight of thefirst fibers and about twenty to forty percent by weight of the secondfibers.
 8. A method as recited in claim 1, in which the second fibersare LCP and Aramid fibers.
 9. A method as recited in claim 8, in whichthe blended yarn comprises about fifteen to thirty-five percent byweight of the first fibers and about sixty-five to eighty five percentby weight of the second fibers.
 10. A method as recited in claim 1, inwhich the first fibers are HMPE fibers.
 11. A method as recited in claim1, further comprising the step of forming a braided rope formed from aplurality of blended yarns.
 12. A method as recited in claim 11, inwhich the step of forming the braided rope further comprises the step offorming a core and a jacket.
 13. A method as recited in claim 11, inwhich the step of forming the braided rope further comprises the step offorming a double braided rope.
 14. A method as recited in claim 1,further comprising the steps of: combining a plurality of the blendedyarns to form a plurality of strands; and combining the plurality ofstrands are combined to form a rope.
 15. A method of forming a ropecomprising the steps of: providing a first set of first fibers;providing a second set of second fibers; combining the first and secondsets of fibers to form a plurality of wrapped yarns such that the firstset of the first fibers forms a core that is substantially surrounded bythe second set, the first fibers substantially determine the loadbearing characteristics of the rope, and the second fibers substantiallydetermine abrasion resistance properties and gripping ability of therope; and applying a tension load on the rope such that the tensionloads on the rope are primarily borne by the first fibers, and thesecond fibers substantially determine friction, abrasion resistance, andgripping ability of the rope.
 16. A method as recited in claim 15, inwhich the second fibers at least partly surround the first fibers.
 17. Amethod as recited in claim 15, in which the first fibers are formed ofHMPE and the second fibers are formed of polyester.
 18. A method offorming a blended yarn comprising the steps of: selecting a plurality offirst fibers and a plurality of second fibers such that a coefficient offriction of the second fibers is greater than a coefficient of frictionof the first fibers, abrasion resistance characteristics of the secondfibers are greater than abrasion resistance properties of the firstfibers, and a gripping ability of the second fibers is greater than agripping ability of the first fibers; combining the plurality of secondfibers with the plurality of first fibers using a false-twisting processsuch that the first fibers extend along the length of the blended yarnand the second fibers do not extend along the length of the blendedyarn, and at least a portion of the second fibers are engaged with andextend from the plurality of first fibers effectively to define surfacecharacteristics of the blended yarn; and applying a tension load to theblended yarn such that the tension loads on the blended yarn areprimarily borne by the first fibers, and the second fibers substantiallydetermine friction, abrasion resistance, and gripping ability of theblended yarn.
 19. A method as recited in claim 18, in which the secondfibers at least partly surround the first fibers.
 20. A method asrecited in claim 18, in which at least a plurality of the first fibersare continuous and at least a plurality of the second fibers arediscontinuous.